indentation and other minor cleanup

[nyurik]

• cleaned up all indentations, a few tabs->spaces
• use multiline template string instead of '\n'
• a few missing semicolons
• removed unused 'lodash' dependency (not even in package.json)
• convert remaining vars to consts
• replaced obsolete <center> with <div> with embedded CSS

[PhaedrusTheGreek]

Thanks @nyurik